bug 838638 - search overhaul

This overhauls search to use the latest elasticutils, pyelasticsearch and redoes the infrastructure to unblock such diverse things as synonyms, locale-specific analyzers, document-level boosts, index settings, indexing other things, etc.

You definitely want to review commits one at a time so you can skip the one that adds six.

I wrote up a test plan here:

https://etherpad.mozilla.org/sumo-search-overhaul-2013-test-plan-of-doom

It's kind of a pain in the ass.

My suggestion is to:

1. read through the stage 1 and stage 2 commits and comment where you desire -- feel free to ask questions
2. go through the test plan -- feel free to go off the rails if you think of things that should get tested that aren't in the test plan

r?